Healer is not a must have, you can choose to become a champion of the god Nit to get a vampirism buff and focus on damage.
For the last boss fight remember to buy all the temple buffs, they help A LOT. Try to get many stun/cc skills.
For reference, I managed to clear hardcore with this team:
- Fire mage, full points on magic, fire and doodge; 1 skill point for stealth.
- Melee with dagger (rogue), full points on doodge and stealth, some points on attack and 1-hand weapons.
- Tank with sword and shield, full points on defense and dark magic (all skills), 1 skill point on law magic for damage on summons.
- Nit champion buff for vampirism heals.
- Lightning spell.
The evil pandas, the ones who destroyed barbearians' home, are called "Qin", "Sui", "Jin", "Shang", "Han", "Liao" ... Chinese names... does that means something? Jayarmstrong is trying to warn us.
Guys, I got general on all maps (Challenge mode, perfect), just go with Engineer, spend talent points for "This is my town 3/3" and buy the "Engineer's path 1/1", then go for "This is my town 5/5" and "Stay still 3/5", at this point you should have unlocked the fourth talent set, upgrade "Deep impact 3/5" and focus all your points on "Greedy bastard 5/5" - With these talents play only with "Rocket towers" (Cost 40), 3 of them are enough for almost every map on challenge mode (ofc you must drive ALL your enemies through one single path with "Barricades" where you placed the "Rocket towers". Don't fire enemies, stay away from the towers and go afk.
I managed to kill the fox king with this formation:
(4) 10/100/14 Shooter
(3) 10/73/24 Shooter
(2) 51/25/31 Shooter
(1) 90/25/16 Melee
85 of energy is enough if you take 2 bottles of milk on your way.
I found a nice trick, If you right-click with the mouse, the game will stop for 3 seconds and in this time you can click in another area for teleport the ball
 "Nuclear Outrun"){kind=icon}
 "Wondrous Lands"){kind=icon}
 "Crusaders of the Lost Idols"){kind=icon}
 "Bearbarians"){kind=icon}
 "Snail"){kind=icon}
 "Bunny Flags"){kind=icon}
 "The Enchanted Cave"){kind=icon}
 "StrikeForce Kitty"){kind=icon}
 "Pandemic 2"){kind=icon}
 "Kill the Heroes"){kind=icon}
 "Particles"){kind=icon}
Level up buttons are scheduled for the Idol Shop.